^g^.gSS"*"}       Notes  on  Pepsin,  Bismuth,  etc.  347 
-was  dissolved,  while  in  B  and  C  the  albumen  did  not  appear  to  have 
been  acted  upon. 
Therefore,  in  C,  the  small  quantity  of  magnesia  which  the  distilled 
water  had  dissolved,  and  with  which  quantity  the  pepsin  had  been  in 
contact  before  the  acid  was  added,  was  sufficient  to  modify  the  pepsin 
and  destroy  its  digestive  action  on  fresh  coagulated  albumen.  In  B, 
the  carbonates  of  the  well  water  had  caused  the  same  result.  In  D, 
the  carbonates  were  destroyed  by  the  addition  of  acid  before  the  pep- 
sin was  added,  and  therefore  the  albumen  was  easily  dissolved.  Such 
proofs,  I  think,  must  necessarily  convince  the  most  skeptic. 
The  physician  might  wish  for  a  combination  of  pepsin  and  bismuth 
in  the  liquid  state,  but  another  question  is,  can  such  a  combination 
be  made,  or  can  it  exist  ?  Those  that  manufactured  the  elixir  of  pep- 
sin and  bismuth  (and  strychnine),  were  satisfied  to  know  that  they 
used  pepsin  in  its  preparation,  but  whether  it  was  in  it  or  in  an  active 
form,  never  troubled  them,  as  they  never  tested  for  it.  They  could 
conscientiously  put  their  label  on  the  bottle,  and  maintain  that  they 
used  pepsin  in  its  preparation.  The  physician  prescribed  it  in  good 
faith,  because  he  had  confidence  in  the  firm  who  made  it,  and  in  the 
name  by  which  the  preparation  was  designated. 
Having  tested  several  elixirs  of  pepsin  and  bismuth  that  I  could 
get  hold  of,  I  found  that  even  after  the  addition  of  hydrochloric  acid 
not  the  least  quantity  of  albumen  was  dissolved. 
Thinking  that  an  acidulated  bismuth  solution  might,  in  combination 
with  pepsin,  prove  more  efficacious  containing  the  pepsin  in  its  active 
form,  my  first  aim  was  to  find  a  bismuth  salt  for  that  purpose. 
Crystallized  ternitrate  of  bismuth  dissolves  in  glycerin,  which  solu- 
tion can  be  diluted  with  a  considerable  quantity  of  water  before  the 
subnitrate  is  precipitated.  This  salt  I  dropped  from  the  list,  as  the 
solution  is  too  acid  and  tastes  too  styptic. 
Freshly  precipitated  subnitrate  of  bismuth,  prepared  with  1  part  of 
crystallized  ternitrate  with  40  parts  of  water  was  put  on  a  filter,  and 
when  entirely  drained  added  to  glycerin,  in  which  it  dissolves,  form- 
ing a  clear  solution,  but  on  the  addition  of  water  the  clear  solution 
becomes  milky  after  some  time. 
I  now  tried  the  action  of  acids  on  ammonio-citrate  of  bismuth. 
For  that  purpose  I  made  two  solutions  of  ammonio-citrate  of  bismuth 
of  the  same  strength,  with  the  difference  that  the  one  solution  was 
made  with  water  alone,  and  the  other  with  a  mixture  of  glycerin  and 
